1. Field of the Invention
This invention relates to a disposable medical device employing electrical signals to monitor or stimulate various parts of the body. More particularly, the present invention involves a device for establishing electrical connection to a patient's skin containing a fixed array of conductive paths of substantially the same electrical resistance for use with an electrocardiological measuring apparatus.
2. Description of the Prior Art
Prior art medical electrodes generally are combination structures including a metallic or otherwise conductive support member to which an electric wire from an assorted apparatus may be attached. Generally, electrocardiograms sometimes referred to as an EKG or ECG have ten cable leads which attach to various points on the upper and mid-torso of a patient to measure and analyze cardiac data.
Of primary concern when preparing for an electrocardiogram is accurate placement of the electrodes. The person responsible for attaching the electrodes and lead wires ("leads") of the EKG often has problems in attaching these multiple leads to the patient because the lead wires may tangle with one another or, in the case of suction-type electrodes, may become detached before or after they are all connected. Accurately placing and securing a large number of leads can be difficult and time consuming and requires the knowledge of a skilled technician or physician.
Periodic electrocardiograms can provide a cardiographic profile of a patient for early detection and diagnosis of cardiovascular diseases. For purposes of providing an accurate profile, it is important not only that the electrocardiogram be taken with sensors affixed accurately, but that the sensors are placed at the same location on the patient as for the previous electrocardiograms. The accuracy of the reproducible results is critical so that a series of electrocardiograms can be compared, between testing episodes, to provide a continuing profile of a patient for diagnosis and treatment of heart disease.
A full screen, ten electrode (twelve lead) electrocardiograph provides the most accurate picture for recognizing ischemic electrocardiographic changes. However, in urgent situations, including those electrocardiograms taken during an acute symptomatic episode of a cardiac patient, only two to four electrodes may be attached to the patient. Therefore, it would be advantageous and desirable to have a device which enables more leads to be accurately placed and quickly secured during an acute symptomatic episode.
On the other hand it may be necessary to quickly remove certain or all of the chest leads of the EKG when a patient is experiencing another heart attack in order to administer CPR, to massage the heart, administer drugs or apply electrical defibrillation paddles. Accordingly, valuable seconds are often lost in removing the chest leads of the EKG device in order to administer aid to the patient.
U.S. Pat. No. 4,328,814 to Arkans teaches a plurality of electrodes arranged in a strip. Each electrode has a conductive lead which runs to a single junction connector having one cable leading to the EKG device. This device is designed for an adult patient so that patients having larger or smaller torsos will have difficulty in using the device because the electrodes cannot be easily adjusted to accommodate a smaller or larger torso.
U.S. Pat. No. 4,353,372 to Ager discloses a plurality of electrodes which plug into a junction box connected to an EKG machine. Each of the electrodes includes wires molded into a central cable system which joins the junction box. This device does not include means for quickly attaching or removing the electrodes. For example, in an emergency situation if the electrodes must be removed quickly, the junction box must be disconnected first and then each of the electrodes must be detached. Although each electrode has a wire lead from the main molded cable, which may permit some adjustment in the placement of the electrodes on the upper portion of a human torso, the device is not entirely adequate for large adults or very small children because of the limited adjustment of each electrode.
U.S. Pat. No. 3,910,260 describes telephonic units for transmitting EKG signals to ECG receiving equipment which could be at a hospital or a physician's office. The transmission may take place in emergency vehicles where prior medical history may not be readily available. In order to obtain meaningful and reliable data ECG signals are necessary for the care providers.
U.S. Pat. No. 4,608,987 to Mills relates to a vest-like garment having a plurality of apertures adapted for receiving associated electrodes. However, the vest is not tailored for a specific patient and proper fit is provided by adjustable straps which may be secured by VELCRO material. Therefore, there is no assurance that the electrodes are placed at the same anatomical location upon reuse with the same patient.
U.S. Pat. No. 4,583,549 to Manoli relates to an ECG electrode pad having a flexible non-conductive pad provided with a plurality of electrodes. In this patent, the electrodes are positioned at various anatomically defined positions on the chest wall. Although different size pads are contemplated, this patent lacks any teaching or suggestion of how the sizes are dimensioned, how they would be determined, or even how a patient would be fitted with the proper size.
U.S. Pat. No. 5,184,620 to Cudahy discloses a multiple electrode pad for monitoring a patient's cardiac electrical activity. A flexible pad is equipped with a plurality of groups of electrodes. In one embodiment each group has two electrodes, and in another embodiment three electrodes form each group.
U.S. Pat. No. 5,224,479 to Sekine illustrates a vest-like ECG diagnostic pad provided with upper limb lead electrodes, precordial lead electrodes and flank lead electrodes. The precordial lead electrodes are positioned on the pad to come into contact with anatomically prescribed locations on the midriff portion of the patient.
U.S. Pat. No. 5,507,290 to Kelly relates to an electrodeless EKG sensor sheet provided with electrical conducting strips or wires. The sensor sheet is made of a flexible, non-conductive substrate and can include means for positioning the sheet on the chest of a patient. The electrical conducting strips are set in a predetermined pattern on the sensor sheet. The patent does not relate to providing different size sensor sheets.
None of the prior art devices disclose a low cost solution for obtaining repeatable placement of sensors for accurate and readable ECG signals in the field by unskilled individuals.
Because of the inadequacies of prior art devices there is a need for a system which prevents EKG electrode leads from being entangled; provides quick removal of some of the electrodes while leaving the remaining electrodes in position when it is necessary to administer aid to a patient having a heart attack; provides accurate repeatable placement of electrodes at substantially the same anatomical location; accurately and repeatedly obtains signals from body electrodes by efficient and effective electrical transmission; may be attached by unskilled persons; and may be available in various sizes to accommodate different size patients.